#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int main() {
	char letters[] = { 'F','E','D','C','B','A' };
	int i, j;
	for (i = 0; i < 6; i++) {
		for (j = 0; j <i + 1; j++) {
			printf("%c", letters[j]);
		}
		printf("\n");
	}
	return 0;
}